Oklahoma will be in the College Football Playoff when the field is officially announced on Sunday, and there’s a good chance none of the other three semifinalists will have a unit-wide weakness as publicly-acknowledged as the Sooners’ defense. Oklahoma sits in the middle of the pack nationally in yards per game allowed and gave up 35 points or more four different times during the regular season, which didn’t raise eyebrows in the pass-happy Big 12 but dragged down its national reputation as the top tier of championship contenders took shape.

But over the course of the year, the Oklahoma D has produced considerable evidence that it knows when the big games are. First, there was September’s 31–16 win over Ohio State in Columbus, which sent the Buckeyes’ offense spiraling into a temporary existential crisis. Then there were hard-hitting wins over Texas and TCU that solidified the Sooners’ place at the top of the conference standings. Saturday’s 41–17 win over the Horned Frogs in the Big 12 title game was the latest and most emphatic sign that the Sooners’ supposed Achilles’ heel may not be as exposed as everyone thought: TCU was held to 317 yards, its third lowest output of the year, and were forced into two costly turnovers.

It didn’t take long for the first mistake to arrive. After Oklahoma opened with a field goal, TCU running back Kyle Hicks was stripped on the Frogs’ first play from scrimmage, and Caleb Kelly scooped up the loose ball and returned it 18 yards for the score.

The Sooners put the clamps on TCU’s offense with help from a critical adjustment to limit quarterback Kenny Hill’s ability to run. Hill picked up 18 yards On its second possession of the second half, TCU tried to pick up a fourth-and-inches in Oklahoma territory by sending Hill on a bootleg, but Ogbonnia Okoronkwo and Parnell Motley beat him to the boundary and knocked him out just short of the line to gain. Two plays later, Baker Mayfield hit Marquise Brown for a 55-yard touchdown to extend the lead to 21.

As the game got out of hand later in the third quarter, Hill began to push and made another mistake, floating a throw down the sideline that was picked off by Will Johnson. From there, the Sooners went into clock-melting mode, limiting the Horned Frogs to only two more drives and five more minutes of possession the rest of the way.

Ahead of the first Big 12 title game since 2010, conference partisans had spent most of the week sweating out the implications of putting the league’s best team up for a rematch with a College Football Playoff bid nearly in hand. After reaffirming their supremacy on both sides of the ball—all Heisman front-runner Mayfield did was go 15 of 23 through the air for 243 yards and four touchdowns—the Sooners look like a team no one wants to line up against when the bright lights come on.